Ultrafine AIN particles were synthesized by chemical vapor deposition at 973-1273K. Effects of reaction temperature, totlaflow rate AIC$l_3$ concentration on AIN particle morphology, particle size distribution were studied. Also investigated was the mechanism of the reaction between AIC$l_3$ and N$H_3$. The mechanisms for homogeneous formation of AIN particles and growth of AIN film by surface reactions were investigated.